OOP

Question 1

attr_accessor
attr_reader
attr_writer

Answer 1

attr_accessor :name, height, :weight

self. name
self. height
self. weight

Question 2

call the constant variables and instance method by creating an instance object.

# define a class
class Box
   BOX_COMPANY = "TATA Inc"
   BOXWEIGHT = 10
   # constructor method
   def initialize(w,h)
      @width, @height = w, h
   end
   # instance method
   def getArea
      @width * @height
   end
end

Answer 2

# define a class
class Box
   BOX_COMPANY = "TATA Inc"
   BOXWEIGHT = 10
   # constructor method
   def initialize(w,h)
      @width, @height = w, h
   end
   # instance method
   def getArea
      @width * @height
   end
end

my_box = Box.new(10, 20)
puts my_box.getArea => 200
puts Box::BOX_COMPANY => ‘TATA Inc’
puts “Box weight is: #{Box::BOXWEIGHT}”

Question 3

Write accessor getter and accessor setter methods for the class below.

# define a class
class Box
   # constructor method
   def initialize(w)
      @width = w
   end
end

Answer 3

you get 2 methods and 1 ivar(instance variable) using that code.

class Box
   # constructor method
   def initialize(w)
      @width = w
   end

# accessor methods
def Width
@width
end

   # setter methods
   def width=(value)
      @width = value
   end
end

Question 4

Inheritance, pass an argument from child to parent when initialize or with a method.

Answer 4

Inheritance, pass an argument from child to parent when initialize or with a method.

def a_method(one, two, three)
super(one, three)
end

Question 5

class Person

protected
attr_reader :age

private
attr_reader :name
end

Person

Answer 5

When a method is private, only the class - not instances of the class - can access it. However, when a method is protected, only instances of the class or a subclass can call the method. This means we can easily share sensitive data between instances of the same class type.